Then adopting the connection [1]}
between the equal-time prescription in the rest frame
and the light-cone dynamics, i.e., assuming that the
constituent quarks \(b\)  and \(c\)  are on-shell and their
light-cone momentum fraction are \(x_{b}\)  and \(x_{c}\) ,
with \(x_{b}\)  \(+\)  \(x_{c}\)  \(=\)  1, one can get the
light-cone wave function for \(B_{c}\)  meson,
\({\psi }_{B_{c}}(x_{i},\vec{k}_{\perp })\ {\propto }\ {\exp }\Big \lbrace -\frac{1}{8{\alpha }^{2}}\Big (\frac{\vec{k}_{\perp }^{2}+m_{c}^{2}}{x_{c}}+ \frac{\vec{k}_{\perp }^{2}+m_{b}^{2}}{x_{b}}\Big )\Big \rbrace .\) 
